Hi Stewart,
The Gemini telescope is part of the Sierra stars observatory network (SSON). Have a look at their web site at: http://sierrastars.com/ . If you want to use it you will have to set up an account and then buy some credits. Then you can schedule jobs to look at whatever you want.
A word of caution though, as with most things you usually only see the good images. There are often ‘issues’ with using remote telescopes so don’t expect perfect results every time. Prepare for some disappointments…the image I downloaded this morning was rubbish!!!
Have you looked at iTelescope? They have a wide range of telescope sizes suited to all sorts of observing projects (SSON only have two 0.5M instruments). Payment there is with a monthly subscription but you can change the amount you pay on your ‘Plan’ quite easily.
Hope that helps,
Mike.